Background: Multiple Sclerosis (MS) is an inflammatory with overlapping demyelinating and neurodegenerative phases of the central nervous system (CNS) with large attribution to progressive neurological disability in MS by the latter phase. Grey matter atrophy has been found to have a role in neurodegenerative etiology and has a greater link to impairment than white matter abnormalities. Many investigations have shown a link between leptomeningeal inflammation in the form of ectopic lymphocytic aggregates and cortical disease. Aim of the work: To evaluate the value of detection of Leptomeningeal enhancement in patients with various phenotypes of multiple sclerosis patients as prognostic marker for the clinical course regards prognosis. Patients and Methods: This is prospective research that lasted 16 months and included 52 patients with multiple sclerosis of various phenotypes who attended the Neurology MS clinic at Al-Azhar University Hospitals. The following was done to all of the patients: -Comprehensive history taking, illness severity evaluation using the Expanded Disability Status Scale (EDSS), Symbol Digit Modalities Test at baseline and follow-up, normal laboratory tests Radiological assessment using a 3T MRI brain with contrast and post-contrast FLAIR sequences. Result: The study's findings found a substantial link between presence of leptomeningeal enhancement and EDSS progression Conclusion: 3Tesla MRI brain with post contrast FLAIR in patients with Multiple sclerosis could be used as an in vivo marker for detection of leptomeningeal inflammation which could be used as prognostic marker for progressive disability conversion to SPMS with early aggressive management and individualization of treatment